Selective Monitoring of Hazardous Chemicals in Emergency Situations

Résumé du livre

A recently reported portable instrument for detecting, identifying, and monitoring chemical hazards, developed for alerting U.S. Coast Guard personnel to the presence of hazardous vapors, can monitor all or most of the approximately 30 compounds frequently encountered in JANNAF missions. The instrument uses an array of four different amperometric sensors operating in conjunction with two different noble-metal filaments that may be heated to either 900 C or 1000 C. Operation of the sensor-filament array in four differently selective modes generates 16-parameter response patterns, each of which is characteristic of an individual compound. Histograms and response-versus-concentration plots presented for 17 compounds of interest to JANNAF members show that each compound is distinguishable from the others through its response pattern and that the sensor responses are proportional to the concentration of each compound in the usually encountered ranges (0-50 ppm or, for some compounds, 0-200 ppm). For the subject array, the estimated lower limit of detection ranges from about 0.1 ppm (for acetone, hydrogen sulfide, nitromethane, hydrazine, or chlorine) to 12 ppm (for nitrobenzene).